Hydrogenated block copolymers constituted by conjugated diene monomers and vinyl aromatic monomers, even if not vulcanized, have elasticity similar to that of vulcanized natural rubber and synthetic rubber, at ordinary temperature. Such hydrogenated block copolymers have excellent weatherability and heat resistance, and, at high temperatures, have processability similar to that of thermoplastic resins. Thus, the hydrogenated block copolymers are widely used, for example, in footwear, plastic modification, asphalt modification, viscous adhesive materials, household products, packaging materials for home appliances and industrial parts, toys, automotive parts, medical devices, and the like.
Meanwhile, polypropylene resin compositions, which generally have excellent chemical resistance and mechanical properties, are used in wide range of fields, for example, packaging materials, sundries, machine parts, automotive parts, and medical applications.
By necessity from the viewpoint of environmental issues, development of non-halogen transparent polymer materials has proceeded recently. Particularly in the field of medical tubes, polypropylene resins are used, and there arises a need for softening or transparentizing such resins depending on applications.
The following Patent Literature 1 discloses a tube including a styrene thermoplastic elastomer (a) and a polypropylene resin (b), wherein the elastomer (a) is a hydrogenated block copolymer including a polymer block containing an aromatic vinyl compound (A) and a polymer block containing isoprene and/or 1,3-butadiene (B), the content of polymer block (A) is 5 to 40% by mass before hydrogenation, the ratio of hydrogenation of the polymer block (B) is 70% or more, the content of 1,2-bonds and 3,4-bonds of the polymer block (B) is 30 to 85 mol %, the mass ratio of the styrene thermoplastic elastomer (a) to the polypropylene resin (b) [(a)/(b)] is 90/10 to 40/60, and the ratio of the diffraction peak intensity at a scattering angle of 14° [I(14)] to the diffraction peak intensity at a scattering angle of 15° in X-ray diffraction [I(15)] [I(14)/I(15)] is 1.4 or more.
The following Patent Literature 2 discloses a base material for transporting and preserving a medical solution, containing (A) a propylene polymer and (B) at least one thermoplastic elastomer selected from an ethylene elastomer (B1) and a hydrogenated styrene-diene elastomer (B2).